Part II AUTOMATION

Textbook: Groover M. P.(2008). Automation, production systems, and computer integrated manufacturing, 3rd ed. Prentice Hall.

- Chapter 4: Introduction to Automation - Chapter 5: Sensors, Actuators, and Other Control System

Components - Chapter 9: Discrete Control Using Programmable Logic

Controllers and Personal Computers

CH 4 INTRODUCTION TO AUTOMATION

Automation Defined

Automation is the technology by which a process or procedure is accomplished without human assistance.

“Automation = Automatic Control” §  Basic elements of an automated system:

1. Power - to accomplish the process and operate the automated system

2. Program of instructions – to direct the process

3. Control system – to actuate the instructions

Elements of an Automated System

1- Electricity - The Principal Power Source

§  Widely available at moderate cost

§  Can be readily converted to alternative forms, e.g., mechanical, thermal, light, etc.

§  Low level power can be used for signal transmission, data processing, and communication

§  Can be stored in long-life batteries

Power to Accomplish the Automated Process

§  Power for the process §  To drive the process itself §  To load and unload the work unit §  Transport between operations

§  Power for automation § Controller unit §  Power to actuate the control signals § Data acquisition and information processing

2- Program of Instructions

Set of commands that specify the sequence of steps in the work cycle and the details of each step

§  Example: CNC part program §  During each step, there are one or more activities

involving changes in one or more process parameters §  Examples:

§ Temperature setting of a furnace § Axis position in a positioning system § Motor on or off

3- Control System – Two Types

1. Closed-loop (feedback) control system – a system in which the output variable is compared with an input parameter, and any difference between the two is used to drive the output into agreement with the input

2. Open-loop control system – operates without the feedback loop §  Simpler and less expensive §  Risk that the actuator will not have the intended

effect

(a) Feedback Control System and (b) Open-Loop Control System

(a)

(b)

Example:

Positioning System Using Feedback Control: A one-axis position control system consisting of a lead screw driven by a DC servomotor and using an optical encoder as the feedback sensor

When to Use an Open-Loop Control System

§  Actions performed by the control system are simple

§  Actuating function is very reliable

§  Any reaction forces opposing the actuation are small enough as to have no effect on the actuation

If these conditions do not apply, then a closed-loop control system should be used

Examples of Automation

Day to Day life §  ATM

§  Vending machines

§  Starting of the vehicle

§  Car wipers

Industry §  Painting Robots in the

automobile mfg industry

§  Soldering Machines

§  Automatic capping machines

§  Automatic filling machines

Example: car painting

Example: cars manufacturing

Example: soldering & brazing machine

Example: bottle filling & capping

Example: packaging

Examples of Automation Home Automation

§  Hot water systems. §  Lighting. §  Air conditioning. §  Powered window blinds. §  Garage doors. §  Security systems.

Why Automation is required ?

§  Increase in comfort.

§  More safety.

§  Improve the quality and precision.

§  To do the job for which human beings will not have the capacity.

§  To avoid monotonous work.

Basic Elements of Control System

§ Sensors

§ Actuators

§ Controllers

Chapter 5: Sensors & Actuators Chapter 9: PLC